I took the index on the words, converted the amount to binary, additional 3 zeros, calculated the sha256 digest, took the first Portion of the hexadecimal to transform it to binary, included three zeros into the 8 digits with the binary and received 00000010011 which translates to 19 in decimal. https://lingeriebookmark.com/story8635507/bip39-seed-phrase-fundamentals-explained